Water is a basic ingredient of life. In animals, water supports the digestion of food, transportation and use of nutrients and the elimination of toxins and waste from the body. It is estimated that each person requires a total consumption (i.e. drinking and food stuff preparation) of about 7.50 liters per day (Guy, 2003). This is considered a basic minimum amount of water required per person per day, although a much greater amount is typically consumed.
People throughout the world depend on having safe domestic water supplies. As of the year 2000 it was estimated that at least 1.1 billion people lacked access to safe water, representing about ⅙th of world's population. Lack of a safe domestic water supply is particularly prevalent in rural areas of Asia and Africa (WHO/Unicef 2000) where water is either extremely limited or unsafe to consume without additional treatment measures.
Domestic water typically includes water used for household purposes such as consumption, food preparation, bathing, washing of clothes and dishes, flushing of toilets, vehicle washing, and lawn and garden irrigation. Domestic water use is typically divided into internal household use (bathing, flushing toilets, laundry, cleaning, and cooking); and external household use (lawn and garden irrigation, vehicle washing, and recreational use, i.e., pools, fountains, etc). In rural communities where safe domestic water supply is typically limited, external household use may be discontinued or simply supplied by climatic conditions, i.e., rain and/or snow.
Where internal domestic water is supplied from non-piped sources, an average of 6.60 liters of water is used for washing dishes and clothes and 7.30 liters of water per capita for bathing. By contrast, households having piped water supply show an average use of 16.30 liters of water per capita per day, expected for the same washing and bathing use. This difference in water use illustrates a basic need that communities, which rely on non-piped water, have in obtaining additional or adjuvant safe water supplies. This difference in access to safe water is at least partially responsible for the lower standard of health that afflicts many households having unpiped water sources, i.e., typically rural and/or remote access areas.
Water use can be categorized as “no access, basic access, intermediate access and optimal access.” Within the population served at a basic access level, public health gains are primarily achieved through providing a protected water source(s), promoting good water handling hygiene practices and household treatment of water and other key hygiene behaviors at critical times. Table 1 shows service level categories for comparison with data concerning estimates of present level of coverage by service level. Data indicates that there remains a significant proportion of the world's population, 18%, without access to an improved water supply within one kilometer of their dwelling and that 53% do not have access to an intermediate access level of service (Guy 2003). Given the cost and difficulty in establishing safe water supplies for a community, especially a rural community in a developing country, these service levels would appear to be difficult to overcome.
TABLE 1Categorization of Service levelsService LevelAccess MeasureNeeds metLevel of health concernNo accessMore than 1000 mConsumption - Cannot beVery high. Hygiene not(quantityor 30 minutesassuredassured and consumptioncollected oftentotal collectionHygiene - Not possible (unlessneeds may be at risk. Qualitybelow 5 l/c/d)timepracticed at source)difficult to assure; emphasison effective use and waterhandling hygieneBasic accessBetween 100 andConsumption - Should beMedium. Not all requirements(average quantity1000 m or 5 to 30assuredmay be met. Quality difficultunlikely tominutes totalHygiene - Hand washing andto assureexceed 20 l/c/d)collection timebasic food hygiene possible;laundry/bathing - difficultunless carried out at sourceIntermediateWater deliveredConsumption - AssuredLow. Most basic hygiene andaccess (averagethrough one tapHygiene - all basic personalconsumption needs met.quantity about 50on-plot (or withinand food hygiene assured;Bathing and laundry possiblel/c/d)100 m or 5 minutelaundry and bathing - Shouldon-site, which may increasetotal collectionalso be assuredfrequency of laundering. Issuestime)of effective use still important.Quality more readily assured.Optimal accessWater suppliedConsumption - all needs metVery low. All use can be met,(average quantitythrough multipleHygiene - All needs should bequality readily assured.100 l/c/d andtaps continuouslymetabove)
The estimated quantities of water at each service level may reduce where water supplies are intermittent and the risk of ingress of contaminated water into domestic water supplies will increase. Where optimal access is achieved, but the supply is intermittent, a further health risk may result from the compromised functioning of waterborne sanitation systems.
Diseases caused by ingestion of water contaminated by human or animal excrement, which contain pathogenic microorganisms, are categorized belonging to water-borne diseases (see Table 2). Water borne diseases mainly include cholera, typhoid, amoebic and bacillary dysentery and other diarrheal diseases. In addition, water-borne disease can be caused by the pollution of water with chemicals that have an adverse effect on health. However, diseases caused by the pollution of water by chemicals come under the emerging trend of additional water treatment needs.
Water-washed diseases are caused by poor personal hygiene, insufficient body washing and skin and eye contact with contaminated water. These include scabies, trachoma, typhus, and other flea, lice and tick-borne diseases.
Diseases caused by parasites found in intermediate organisms living in contaminated water belong under the group of water-based diseases. The main water-based diseases include Schistosomiasis and Dracunculiasis.
The main cause of Water-related diseases is insect vectors, especially mosquitoes, which breed or feed near contaminated water. The common water-related diseases include dengue, filariasis, malaria, onchocerciasis, trypanosomiasis and yellow fever.
TABLE 2Diseases Related to Water (Yenisel Cruz):
Lack of safe water is reported responsible for 80 percent of illnesses and deaths in developing world (Yenisei Cruz). Elsewhere across the globe, water borne diseases may be attributed as responsible for 80 percent of illness and deaths in the developing world.
A significant amount of disease can be prevented, especially in developing countries, through better access to safe water supply, adequate water treatment facilities and better hygiene practices.
Comparison of statistics indicates progress in rural water supply development in terms of percentage of population supplied with water (quantity), but there is some regression in urban water supply mainly because of population drift from rural to urban areas. It is estimated that domestic water use in developing countries will raise six folds over the coming four decades. The increase will place severe strains on surface and ground water supplies. Therefore, there is an increasing need to provide safe domestic water supplies, especially in developing and rural areas of the world.
The present invention is directed toward overcoming one or more of the problems and goals discussed above. The solutions provided by the present invention are particularly effective in relation to small and/or rural communities in need of local, safe water supplies.
Against this backdrop the present invention has been developed.